[ Eq(Derivative(x1, t), (1*k4*k1/(k6**k3 + x2**k3) + (-1)*k4*x1/k2/(1 + x1/k2))/k4),
  Eq(Derivative(x2, t), (1*k4*k1/(k7**k3 + x3**k3) + (-1)*k4*x2/k2/(1 + x2/k2))/k4),
  Eq(Derivative(x3, t), (1*k4*k1/(k5**k3 + x1**k3) + (-1)*k4*x3/k2/(1 + x3/k2))/k4) ]